Software HLM (Scientific Software International, SSI): How can I find out which structure of the variance covariance matrix was used?

#1
Dear members,
I am currently running a 2-level hierarchical linear model with HLM (Scientific Software International, SSI) and I was wondering
1) how to find out, which structure of the variance covariance matrix was used in the analysis (e.g. Toeplitz, autoregressive, unstructured matrix etc.)?
2) Can I compare AIC/BIC indices in order to arrive at the decision to use a certain structure?
And 3) it possible to determine the effect size for significant level-2 predictors in HLM (SSI)?

Thank you very much for your help!